Crop circles, Google Earth, and the logo mystery

On Google's homepage today, the search giant swapped out its normal logo for a UFO-themed Google doodle. The illustrated flying saucer carved out "Goog e" in the corn field, and a little green tractor finishes off the "l."

Such logo swaps are common for the tech titan, but what are they celebrating? Most of these "doodles" are tied to a particular anniversary or celebrity birthday. Why crop circles? Why today?

To add to the mystery, Google posted the coordinates "51.327629, -0.5616088" in a cryptic Twitter tweet. Curious searchers identified the spot as Horsell, England. Sci-Fi aficionados may recognize the name. In "War of the Worlds," HG Wells wrote that Horsell residents witnessed the first UFO landing.

This has some Google watchers, including Guardian reporter John Vidal, insisting that the new logo is "almost certainly a viral marketing campaign teasing people ahead of some launch in a week or two. One possible explanation is that it's trailing an online 'happening' that will coincide with the 143rd anniversary of Wells's birth next week."